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Erratic Tach reading after Ignition Control Module (power stage) Replacement 900 1993

1993 940T w/180k. Original problem was intermittent stalling at speed but easy restart. Fuel pump, filter, and pressure regulator changed at 150k. Fuel pump relay was original and changed with no effect. As stated on numerous post the Ignition Control Module was high on list of suspects. Replaced the ICM and it runs great. Created new problem though. When accelerating the tach goes wild to the up side. At idle or constant speed it may tick up on occasion. My schematic is poor but the tach appears to receive a signal from the ICM.
The signal is on the same thread as the coil but again it runs fine. New problem or defect in new ICM? Radio Suppression Relay is original and new one on order.






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New Erratic Tach reading after Ignition Control Module (power stage) Replacement [900][1993]
posted by  maestro  on Thu Aug 30 02:05 CST 2007 >


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